Smell and taste dysfunction after covid-19

The sense of smell is an ancient and vital perception in mammals, with the olfactory receptor gene family making up 1% of the mammalian genome, and the human olfactory system being able to discriminate among thousands of airborne chemicals at concentrations below the detection limits of the most complex analytical systems. However, people only realise the importance of smell when it is lost. The covid-19 pandemic has put both smell and taste disturbances in the spotlight because of the functional impact and severe distress caused by the loss of these senses, their fundamental diagnostic value, and, more recently, the high rate of long term dysfunction. The linked meta-analysis by Tan and colleagues (doi:10.1136/bmj-2021-069503) gives a clear picture of the challenge humans face. About 5% of people report smell and taste dysfunction six months after covid-19, and, given that an estimated 550 million cases of covid-19 have been reported worldwide as of July 2022, large numbers of patients will be seeking care for these disabling morbidities. Health systems should therefore be ready to provide support to these patients who often report feeling isolated when their symptoms are overlooked by clinicians.